Currently available online only in OpenBook format, a free pre-publication version of Who Goes There?: Authentication Through the Lens of Privacy, Stephen T. Kent and Lynette I. Millett, Editors, Committee on Authentication Technologies and Their Privacy Implications, National Research Council. The report provides analysis of and recommends guidelines for the development, implementation and deployment of authentication systems that include passwords, public-key infrastructures (PKI), smartcards and biometrics.